Not that they did well out of it. Their empires fell, and in the "winners", their class was almost annihilated (I guess noblesse oblige was good for something). But we got the worse end of the deal. Their selfish war fucked up the entire twentieth century: the Russian Revolution, the inevitable rematch with Germany, and the subsequent Cold War can all be traced to the First World War. And we're still living with the aftermath, in the shape of the contradictorypromises made by Britain to conquer the Middle East, and the artificial countries it left there.

The First World War is a warning of the danger of giving our political elites the power to wage war. While their stupidity couldn't kill all of us then, it can now. Stupidity, greed and selfishness being inevitable amongst elites, the only way we can defend ourselves from them is to disarm them. Peace is our only protection. And next time they tell us to fight, we should tell them to go fuck themselves.